The present invention relates to a method of reusing a rechargeable battery to form a regenerated assembled battery by combining rechargeable batteries of a plurality of assembled batteries collected from users.
An assembled battery formed by a plurality of rechargeable batteries is used as a power source for an electric vehicle, a hybrid electric vehicle, and the like. Studies are being conducted to reuse such assembled batteries, which are used as power sources for vehicles. In this study, assembled batteries are collected from users to rebuild an assembled battery that can be reused by a user. A used assembled battery has battery characteristics (overcharge, overdischarge, voltage variations caused by memory effect, total charge-discharge electrical capacity, etc.) that vary from an unused assembled battery. In addition, the battery characteristics of an assembled battery vary differently depending on the usage environment and usage frequency. The battery characteristics also vary between the rechargeable batteries that form an assembled battery due to individual differences between the rechargeable batteries. Therefore, from the rechargeable batteries of the collected assembled batteries, those having superior battery characteristics are selected and combined to rebuild an assembled battery.
In the selection of collected rechargeable batteries, the rechargeable batteries must be evaluated or inspected. Japanese Patent No. 2727149 and Japanese Patent No. 3364049 describe examples of such evaluations. Japanese Patent No. 2727149 describes a process for determining the state of the battery characteristics for a used rechargeable battery from a discharge characteristic curve. This process is based on the fact that the discharge characteristics vary as the use of a rechargeable battery continues. Japanese Patent No. 3364049 describes a process for evaluating the lifespan of a rechargeable battery. In this process, the relationship between the electrolyte amount of a rechargeable battery and the charge capacity (battery capacity) is evaluated beforehand. Then, the residual amount of the electrolyte is predicted from changes in the measured weight of the rechargeable battery. The lifespan of the rechargeable battery is predicted based on such a measurement.